Review of Autonomous Undersea Vehicle (AUV) Developments 
At each measurement site, the instrument assembly with benthic chambers and oxygen 
microprofiler is slowly lowered into the sediment while being monitored by the two video 
cameras. Once implanted in the sediment, the central controller commands the benthic 
chamber controllers to begin their measurement cycles. The cycle begins by lowering the stir 
motor assemblies to seal the top of the chamber and starting the slow rotation (~9 rpm) of the 
stir bars. The oxygen level in the benthic chambers is measured for a period of 1-7 days, which 
is determined by the central controller. After the completion of an incubation period, the stir bars 
are stopped and retracted, and the instrument rack is raised above the surrounding bumper. 
After sequential sampling for periods up to six months (~30 sites), the instrument and current 
rotor and vane assemblies are retracted into their protected positions, and the ROVER is 
commanded to release its ballast and return to the surface. At the surface, the ROVER is 
located using the directional VHF transmitter and strobe. 
Four-Month Deployment 
The ROVER was deployed for a 4-month period beginning January 28, 1996 at Sta. M (34° 
50'N, 123° 00' W; 4,100-m depth) 220 km west of the central California coast from the R/V 
Wecoma. The microprofiler was not used during this deployment, but SCOC was measured 
within the two benthic chambers. The ROVER was programmed to occupy 17 sites during the 
deployment with incubation periods of the benthic chambers at each site set for ~6 days. 
At the end of the 4-month deployment, the ROVER was recovered on June 1, 1997 using the 
R/V New Horizon. Analysis of the central controller data showed that the ROVER had 
completed its mission of crawling to the 17 measurement sites. Benthic chamber data and 
video recordings showed the chamber design largely performed its mission and useful data was 
recovered from most sites. The time-lapse camera operated correctly and returned many 
photos taken of the sea floor while traveling between measurement sites. 
This ROVER is particularly suitable in remote areas, such as polar regions or mid-basin portions 
of the Pacific and Indian Oceans that are difficult to occupy routinely due to logistical or weather 
constraints. It also can be operated at a fraction of the cost of using manned submersibles or 
tethered ROVs, especially in these remote or weather-limited areas. 
The ROVER can be used as a programmable platform from which to conduct a wide variety of 
research, including photographic transects, fine-scale bottom-water profiling for nutrients, fine- 
scale mapping of sea floor relief, and fine-scale mapping of sediment properties using 
sequential sediment cores and shear vanes. The increase in sampling resolution provided by 
the ROVER over conventional techniques should provide valuable insights into the dynamics of 
carbon cycling in the deep-sea benthic boundary layer. 
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